On Tue, Nov 19, 2024 at 09:07:45AM -0800, Breno Leitao wrote:
#endif bool enabled; bool extended;
- /* Check if CPU NR should be populated, and append it to the user
* dictionary.*/- if (child_count < MAX_USERDATA_ITEMS && nt->userdata_auto & AUTO_CPU_NR)
scnprintf(&nt->userdata_complete[complete_idx],MAX_USERDATA_ENTRY_LENGTH, " cpu=%u\n",raw_smp_processor_id());I guess it may be tricky for backward compat, but shouldn't we return an error rather than silently skip?
yes, this should be easy to do, in fact. Probably return -E2BIG to userspace when trying to update the entry. I thought about something as the following patch, and piggy-back into it.
Back to this topic, in fact, this is not needed at all.
The configfs make item helper (userdatum_make_item()) checks for exceeding entries, and fails if an additional entry is created.
static struct config_item *userdatum_make_item(struct config_group *group, const char *name) { .... child_count = list_count_nodes(&nt->userdata_group.cg_children); if (child_count >= MAX_USERDATA_ITEMS) return ERR_PTR(-ENOSPC);
I've sent an additional test for this mechanism, and make the check in update_userdata() a warning instead of just silently dropping the entry.
https://lore.kernel.org/all/20241204-netcons_overflow_test-v1-0-a85a8d0ace21...